镀铬企业周边全氟辛烷磺酰基化合物环境风险评价

根据欧盟技术指导文件和EUSES模型预测了镀铬企业全氟辛烷磺酰基化合物(PFOS)排放和周边环境浓度,并对周边水体进行环境风险评价.结果表明,镀铬企业周边环境淡水、海水、淡水沉积物、海水沉积物中PFOS浓度分别为10-7,10-8,10-9,10-10,10-7kg/m3数量级.镀铬企业周边淡水水体风险表征比>1,呈现显著的环境风险.     

单环硝基芳香化合物好氧生物降解及其遗传学研究进展

硝基芳香化合物是环境中难降解的有机污染物之一 ,对环境的污染日益严重 ,利用生物技术对这类有机物进行降解是行之有效的新途径。针对几种单环硝基芳香化合物好氧降解的微生物、降解途径以及降解过程中的主要酶、降解性质粒、基因定位等分子遗传学的研究进展进行了综述     

固定化铜绿假单胞菌生物降解对硝基苯酚

用海藻酸钠作载体,将一株能以对硝基苯酚(PNP)为唯一碳源和氮源的铜绿假单胞菌（Pseudomonas aeruginosa）进行固定化包埋,利用正交试验确定该菌株固定化细胞制备的最优条件,探讨固定化细胞技术对PNP的生物降解效果及其影响因素。结果表明,该菌株的固定化细胞对PNP的生物降解速度大于游离细胞;固定化细胞对PNP的耐受浓度比游离细胞高;固定化细胞生物降解PNP的最适pH为8.0～9.0,最适温度为30～35 ℃。该固定化细胞在PNP浓度为50 mg/L的无机盐溶液中培养42 h,可使PNP降解率接近100%,其生物降解的时间动力学曲线分为0～35 h和35～42 h两段,其中0～35 h为生长延滞期,35～42 h随着菌株生长的开始,PNP迅速被生物降解,约7 h生物降解完全结束。该菌株的固定化细胞可连续使用3次,生物降解效果稳定。     

生物质热解过程中含氮模型化合物研究进展

由于生物质成分的复杂性,直接热解生物质很难获得其氮转化机理,利用含氮模型化合物热解成为近年来研究生物质NO_x生成机理的主要方式。首先总结了燃料氮在生物质中的赋存形态及其常用的模型化合物,综述了蛋白质、环二肽、氨基酸等模型化合物热解的一般机理,并对影响模型化合物热解路径的化学成分、热解温度、升温速率、含氧量等因素做了分析。目前,通过模型化合物热解研究,研究人员可以得到生物质中燃料氮的转化机理,但有些机理还存在一些争议,结合计算化学理论分析可能获得更清晰的NO_x生成机理。     

ECHA就镉、铅和壬基酚行动征求意见

正2013年12月19日ECHA发起了多项与限制相关的信息征求和意见征询。它们包括:1)一次关于由ECHA提出的一项修订关于油漆中的镉及其化合物的现行限制(附录17第23条的一部分)的提议的意见征询。针对该提议的评议应在2014年6月17日前提交给ECHA;2)一项关于针对壬基酚(NP)和羟乙基壬基酚酯(NPE)的提议限制的额外信息征求,以帮助社会经济分析委     

污水生物脱氮工艺分析

本文通过生物脱氮原理的简要分析,详细论述了实践中常用的活性污泥法、缺氧—好氧活性污泥两种脱氮工艺.     

Effect of platinum on the photocatalytic degradation of chlorinated organic compound

TiO2 nanoparticles, doped with di erent Pt contents, were prepared by a modified photodeposition method using Degussa P-25 TiO2, H2PtCl6 6H2O and methanol as the solvents. The physicochemical properties of Pt/TiO2 were investigated by the nitrogen adsorption and desorption isotherm measurement technique, X-ray di raction analysis and photoluminescence spectra, respectively. Reaction rates from photocatalytic removal of dichloromethane over Degussa P-25 TiO2 and Pt/TiO2 were evaluated. The average diameter and BET surface area of the TiO2 catalyst particles were 300 nm and 50 m2/g, respectively. The degradation e ciency was 99.0%, 82.7%, 55.2%, and 57.9% with TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. And the degradation e ciency was 99.3%, 79.7%, 76.5%, and 73.4% with a 0.005 wt.% Pt/TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. In addition, we found that the photoluminescence emission peak intensities decreased with increases in the doping amount of Pt, which indicates that the irradiative recombination was weakened. Furthermore, the results showed that the UV/0.005 wt.% Pt/TiO2 process was capable of e ciently decomposing gaseous DCM in air.     

Impacts of wastewater sludge amendments in restoring nitrogen cycle in p-nitrophenol contaminated soil

The possible impacts on nitrogen-cycle in a p-nitrophenol (PNP) polluted soil and the e ectiveness of wastewater sludge amendments in restoring nitrification potential and urease activity were evaluated by an incubation study. The results indicated that PNP at 250 mg/kg soil inhibited urease activity, nitrification potential, arginine ammonification rate and heterotrophic bacteria counts to some extents. After exposure to PNP, the nitrification potential of the tested soil was dramatically reduced to zero over a period of 30 days. Based on the findings, nitrification potential was postulated as a simple biochemical indicator for PNP pollution in soils. Nitrogen-cycling processes in soils responded positively to the applications of wastewater sludges. A sludge application rate of 200 tons/ha was su cient for successful biostimulation of these nitrogen processes. The microbial activities in sludge-amended, heavy PNP-polluted soils seemed to recover after 30–45 days, indicating the e ectiveness of sludge as a useful soil amendment.     

Modeling the influence of ethanol on the adsorption and desorption of selected BTEX compounds on bentonite and kaolin

The study investigated the effects of ethanol on the adsorption properties of bentonite and kaolin for benzene and toluene removal.     

Beyond hypoxia：Occurrence and characteristics of black blooms due to the decomposition of the submerged plant Potamogeton crispus in a shallow lake

Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.